Cooling water can be from any source, but the following basic requirements are needed:
1. Water should be clean.
2. Water temperature should be between 5 and 30°C.
3. The pressure delta between the inlet and outlet should be 207-275kPa.
4. The flow rate specified for the equipment must be available at all times.
Because the quantity of water required is too expensive to draw from a city water system and dump down the sewer without recirculation (and possibly illegal), most customers select external cooling systems, sold and installed by other suppliers, that re-circulate the water. This is especially beneficial when more than one system is involved, as one cooler can handle multiple systems. There are two types of coolers:
Evaporative coolers (Cooling Towers) which use the evaporation of a water spray to cool the recirculating water. This method still consumes some water via the evaporation and cannot cool to lower temperature.
Chilled coolers, which use a refrigeration system to cool the water. This system then uses an air-cooled condenser to expel the heat outdoors.
Either system may use ethylene glycol (antifreeze) mixed with the water to extend the temperature range of the cooling loop, mostly to avoid freezing. The use of anti-freeze makes the cooling less efficient, which means a higher overall flow rate is required.
